<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>p8_固定定位</title>
    <style>
       .fu { background-color: #ff0; }
       .fu>div {
           width: 100px;
           height: 100px;
       }
       .z1 { background-color: #f00; }
       .z2 {
           background-color: #0f0;
           /* 固定定位:会脱离文档流 释放布局空间
            移动参照物:html根元素 */
           position: fixed;
           right: 0;
           bottom: 0;
       }
       .z3 { background-color: #00f; }
    </style>
</head>
<body>
    <!-- .fu>.z*3 -->
    <div class="fu">
        <div class="z1"></div>
        <div class="z2"></div>
        <div class="z3"></div>
    </div>
</body>
</html>